Oriented columnar films of a polar 1,2,3-triazole-based liquid crystal prepared by applying an electric field

Nguyen, Manh Linh; Shin, Tae Joo; Kim, Ho-Joong; Cho, Byoung‐Ki

doi:10.1039/c7tc02710a

“…This homeotropic column orientation under an E-field can be confirmed by performing an in situ 2D XRD experiment on abulk-level thick film (an ITOc ell with ag ap of 250 mm). [17] TheX RD data in the absence of an E-field presents circular patterns in both the small-and wide-angle regions,w hich imply that the column orientations are random (Figure 3c). On the other hand, the XRD data obtained under an E-field of 16 V pp mm À1 shows spotty reflections that are identical to the GIXS data of the homeotropically oriented sample (Figure 3d;Figure S3).…”

Section: Methodsmentioning

confidence: 97%

Ferroelectrically Switching Helical Columnar Assembly Comprising Cisoid Conformers of a 1,2,3‐Triazole‐based Liquid Crystal

Nguyen

¹

,

Byun

²

,

Kim

³

et al. 2019

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The 1,2,3‐triazole molecule, which is a product of click chemistry, possesses a high dipole moment and can be a useful polar motif for ferroelectric columnar liquid crystal (LC) materials—though it has not been used to date. Herein, we report the helical assembly and ferroelectric switching properties of a columnar liquid crystal comprising a naphthalene core and 1,2,3‐triazolyl linkages. The molecule assembles into a double‐stranded helical columnar LC structure (Colhel). The X‐ray simulations of cisoid and transoid columnar models suggest that the helical assembly comprises cisoid conformers with a non‐zero dipole moment. The helical columns in the Colhel phase are aligned homeotropically under an electric field. The ferroelectric switching of the axial polarization can be observed in the temperature range of 105–115 °C in the Colhel phase, wherein the triazolyl hydrogen bonding along the column axis is weakened. The ferroelectric switching event is attributed to the rotation of the polar triazolyl units in response to the electric field.

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“…Although the primary reflection broadened, the second reflection was still observed (Figure 3a). This indicates a microphase-separated columnar structure (Col dis ) with reduced long-range order [33,34]. The second reflection disappeared at 110 • C, indicating a molecularly mixed Liq state.…”

Section: Thermotropic Propertiesmentioning

confidence: 98%

Bicontinuous Cubic and Hexagonal Columnar Liquid Crystalline Ion-Conductors at Room Temperature in Ion-Doped Dendritic Amphiphiles

Huyen

¹

,

Kim

²

,

Nguyen

³

et al. 2020

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A bicontinuous cubic (Cubbi) liquid crystalline (LC) phase consisting of three dimensional (3D) conducting networks is a promising structural platform for ion-conductors. For practical applications using this fascinating LC structure, it is necessary to suppress crystallization at room temperature (RT). Herein, we report the Cubbi structure at RT and the morphology–dependent conduction behavior in ionic samples of a non-crystallizable dendritic amphiphile. In the molecular design, branched alkyl chains were used as an ionophobic part instead of crystallizable linear alkyl chains. Two ionic samples with Cubbi and hexagonal columnar (Colhex) LC phases at RT were prepared by adding different amounts of lithium salt to the amphiphile. Impedance analysis demonstrated that the Cubbi phase contributed to the faster ion-conduction to a larger extent than the Colhex phase due to the 3D ionic networks of the Cubbi phase. In addition, the temperature–dependent impedance and electric modulus data provided information regarding the phase transition from microphase-separated phase to molecularly mixed liquid phase.

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“…Unlike the typical fanlike‐texture of the Col hel phase in the absence of an E‐field (Figure a), the oriented sample does not exhibit birefringence, which indicates a homeotropic alignment of the columns (Figure b). This homeotropic column orientation under an E‐field can be confirmed by performing an in situ 2D XRD experiment on a bulk‐level thick film (an ITO cell with a gap of 250 μm) . The XRD data in the absence of an E‐field presents circular patterns in both the small‐ and wide‐angle regions, which imply that the column orientations are random (Figure c).…”

Section: Figurementioning

confidence: 99%

Ferroelectrically Switching Helical Columnar Assembly Comprising Cisoid Conformers of a 1,2,3‐Triazole‐based Liquid Crystal

Nguyen

¹

,

Byun

²

,

Kim

³

et al. 2019

Self Cite

View full text Add to dashboard Cite

The 1,2,3‐triazole molecule, which is a product of click chemistry, possesses a high dipole moment and can be a useful polar motif for ferroelectric columnar liquid crystal (LC) materials—though it has not been used to date. Herein, we report the helical assembly and ferroelectric switching properties of a columnar liquid crystal comprising a naphthalene core and 1,2,3‐triazolyl linkages. The molecule assembles into a double‐stranded helical columnar LC structure (Colhel). The X‐ray simulations of cisoid and transoid columnar models suggest that the helical assembly comprises cisoid conformers with a non‐zero dipole moment. The helical columns in the Colhel phase are aligned homeotropically under an electric field. The ferroelectric switching of the axial polarization can be observed in the temperature range of 105–115 °C in the Colhel phase, wherein the triazolyl hydrogen bonding along the column axis is weakened. The ferroelectric switching event is attributed to the rotation of the polar triazolyl units in response to the electric field.

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Oriented columnar films of a polar 1,2,3-triazole-based liquid crystal prepared by applying an electric field

Abstract: A polar liquid crystal based on the 1,2,3-triazolyl group forms high-quality oriented columnar films under an electric field.

Cited by 18 publications

References 63 publications

Ferroelectrically Switching Helical Columnar Assembly Comprising Cisoid Conformers of a 1,2,3‐Triazole‐based Liquid Crystal

Ferroelectrically Switching Helical Columnar Assembly Comprising Cisoid Conformers of a 1,2,3‐Triazole‐based Liquid Crystal

Bicontinuous Cubic and Hexagonal Columnar Liquid Crystalline Ion-Conductors at Room Temperature in Ion-Doped Dendritic Amphiphiles

Ferroelectrically Switching Helical Columnar Assembly Comprising Cisoid Conformers of a 1,2,3‐Triazole‐based Liquid Crystal

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